Soluble aromatic copolyamides and threads thereof with a high modulus of elasticity and high tensile strength

ABSTRACT

AND 5 TO 50 MOL% OF STRUCTURAL UNITS CONTAINING HYDANTOIN RINGS AND HAVING THE GENERAL FORMULA   The invention relates to copolyamides which have an extremely low water absorption capacity of 1 to 3.5 % but remarkably high tensile strengths of between 7 and 20 g/dtex and moduli of elasticity of between 500 and 11.000 kg.wt/mm2. The copolyamides comprise of from 50 to 95 mol.% of structural units of the general formula

United States Patent [191 Wolf et al.

[ Jan. 21, 1975 [73] Assignee: Bayer Aktiengesellschaft,

Leverkusen, Germany 221 Filed: on. 4, 1973 211 Appl. No: 403,389

[30] Foreign Application Priority Data Oct. 4, l972 [52] US. Cl 260/47 CZ, 260/30.2, 260/30.6 R, 260/30.8 R, 260/30.8 D, 260/32.4, 260/32.6

N, 260/49, 260/63 R, 260/65, 260/78 A,

[51] Int. Cl C08g 20/20 [58] Field of Search 260/47 CZ, 78 R, 49, 78 A, 260/63 R, 857 R, 65

[56] References Cited UNITED STATES PATENTS 3,671.614 6/1972 Kunzel et a1 260/47 CZ Germany 2248662 Primary Examiner-Lester L. Lee Attorney, Agent, or Firm-Plumley & Tyner [57] ABSTRACT The invention relates to copolyamides which have an extremely low water absorption capacity of l to 3.5 but remarkably high tensile strengths of between 7 and 20 g/dtex and moduli of elasticity of between 500 and 1 1.000 kgwt/mm The copolyamides comprise of from 50 to 95 mol.% of structural units of the general formula and 5 to 50 mol% of structural units containing hydantoin rings and having the general formula wherein X, R R R R R R R Ar, Z, Y, Y and Hy have the meaning described in the following specification.

8 Claims, N0 Drawings SOLUBLE AROMATIC COPOLYAMIDES AND THREADS THEREOF WITH A HIGH MODULUS OF ELASTICITY AND HIGH TENSILE STRENGTH This invention relates to aromatic copolyamides 5 which contain hydantoin rings and to threads and fibres with very high tensile strengths and high moduli of elasticity produced from them.

Threads and fibres which have a high modulus of elasticity are already known. They are mainly polycondensates of p-aminobenzoyl chloride hydrochloride (German Offenlegungsschrift No. 1,924,736) and of p-aminobenzhydrazide and terephthalic acid dichloride (German Offenlegungsschrift No. 1,938,282). Fibres of these polycondensates have a very high modulus of 15 elasticity which, in some cases, exceeds that of glass fibres. Compared with glass fibres, these fibres have the advantage of having a lower density; the specific modulus of elasticity of these fibres is therefore substantially higher than that of glass fibres. A disadvantage of these polycondensates, however, is that they are difficult to dissolve. To prepare solutions in polar organic solvents it is necessary to add considerable quantities of inorganic salts (lithium chloride) to the solvents, and these salts must subsequently be removed from the finished threads in time-consuming after-treatment processes because they reduce the resistance of the polycondensates to elevated temperatures.

Other threads and fibres with moduli of elasticity have become known which consist of high molecular weight aromatic polyamides which are soluble in polar organic solvents and which contain recurrent structural units of-the general formula I M II -HN O X NH-C-Ar-C- in which X represents the group R, and R represent, independently of each other, by drogen, C -C alkoxy or alkyl groups or halogen atoms,

R represents hydrogen, halogen, a C -C alkyl or alkoxy group, a nitrile group, a COOR. group or a CONR t-,R group, and

Ar represents a divalent aromatic group,

R. representing hydrogen or a C -C alkyl group and R and R representing, independently of each other, hydrogen or C,C alkyl groups or aryl groups.

Threads produced from polycondensates of formula l were found to have tensile strengths of 5-10 g/dtex and moduli of elasticity of between 4000 and 10,000 kg.wt./mm

Polyamides which contain hydantoin rings are also known (see German Offenlegungsschriften Nos. l,720,687 and 1,720,733). They have the recurrent structural unit of the general formula --HNYHyYZ-NHOC-ArCO- II in which Z denotes a single bond or the groupHy-Y- and Y and Y may be the same or different and represent bivalent aromatic groups which consist of one or more condensed or of several aromatic rings joined together by single bonds or by bridge members such as 37 -O-, -S-, -S0 -C- or -C- or they represent the halogen, C -C alkyl, NO or CN substitution products of such groups,

Hy represents a bivalent hydantoin ring of the for- R represents hydrogen, a C -C alkyl group, a cycloalkyl group or a phenyl group which may be substituted and Ar represents a bivalent aromatic group which consists of one or more condensed or several aromatic rings which are joined together by single bonds or by bridge members such as and the halogen, C -C alkyl, NO or CN substitution .products thereof.

Threads and fibres produced from these polyamides have tensile strengths of between 2 and 4.5 g/dtex and moduli of elasticity of around l0O0'kg.wt./mm The water absorption capacity of these fibres is between 5 and 11 (determined at 20C and 65 relative humidity), depending on the structure of the polyamide.

If copolyamides are prepared from the diamines on which the homopolycondensates I and II are based, the properties of the individual homopolycondensates would lead one to expect that the corresponding copolyamide would have a relatively high water absorption capacity and relatively low tensile strengths and moduli of elasticity due to the loosening up of the structure. 1t was surprisingly found, however, that exactly the opposite is the case. Copolyamides produced in this way have an extremely low water absorption capacity 5 of l to 3.5 but remarkably high tensile strengths of between 7 and 20 g/dtex and moduli of elasticity of between 500 and 1 1,000 kg.wt./mm

More particularly, this invention relates to a highmolecular weight aromatic copolyamide which com- In cases where R,, R or R represent halogen, the

prises from 50 to 95 mols-% of structural units of the halogen is preferably chlorine. If R and R represent general formula I aryl groups, they are preferably phenyl or phenyl groups substituted with chlorine or C -C alkyl groups. The copolyamides according to the invention are therefore built up of 3 components:

1. The first component consists of one or more fully o 0 aromatic diamines corresponding to the general for- I1 -l:lN X NH-C-Ar-C- mula in which H N 0-. -X- -NH III X represents the group 9 9 2 C-NH- or NH-C R and R which may be the same or different, reprein which I Sent hydrogen, an lk group, an alkyl group or R R R and X have the meanings defmed above.

a halogen t The following compounds are given as examples:

R represents hydrogen halogen, an alkyl, an alkoxy group, a nitrile group, a COOR or CONR R -group and Ar represents a divalent aromatic group,

senting hydrogen, an alkyl group or aryl group and 5-50 mols-% of structural units which contain hy- 3 R denoting hydrogen or an alkyl group and H N@ O. -.C..1-IH O -NH 1 R and R which may be the same or different, repre- 2 i dantoin rings, which structural units are represented by the general formula and Y and Y may be the same or different and represent bivalent aromatic groups which comprise one or more condensed or several aromatic rings which are joined together by single bonds or by bridge members and the halogen-, alkyl-, NO or CN- 7 u 1 substitution products of such groups, Hy represents a bivalent hydantoin ring of the for- Z O-@ C NH Z. 3)

mula V R O H O 41M? l7 R C 0 N C N I 3 v u O H N O@NH- @-NH I 4) in which 01 l R represents hydrogen, alkyl, cycloalkyl, a phenyl group or a substituted phenyl group and 8 Ar represents a bivalent aromatic group, H N O 0- -NH-C NR g 5) the copolyamides having a relative solution viscosity v (determined on a 0.5 solution of the copolyami'de in concentrated sulphuric acid at 25C) of 1.5 to 3. H

. O in which 40 I Z represents a single bond or the group Hy--Y 2 2 2) v ylethers s l i lllh' O N N- O NH i ll These diam ines may be prepared according to known processes, for example by reacting 3-(4-nitrophenox- 'y)-benzoic acid chloride with the corresponding substituted or unsubstituted 4-nitroaniline and reducing the resulting dinitro compound or by reacting a substituted or unsubstituted 3-amino-4'-nitrodiphenylether with 4-nitrobenzoyl chloride or substituted 4-nitrobenz0yl chloride and then reducing the resulting dinitro compounds. These dinitro compounds can be obtained from substituted or unsubstituted 4- nitrophenoxybenzoic acid and substituted or unsubstituted 4-nitroaniline or from the aminonitrodiphenand substituted or unsubstituted 4- nitrobcnzoic acid in N-methyl pyrrolidone in the presence of P 0 The second component consists of one or more diamines corresponding to the general formula in which Z, Y, Y and Hy have the meanings defined above. The following diamines are given as examples:

CH O

5 CHE-l2 1 e Aw g ,0 e r H2N@N\ y/ N@NH2 1 {i a o H a l 5 o y T H2N-@O @N\ N @NH2 15) F l cu -c 0 These diamines are added in proportions of to 50 mols-%, preferably l0 to mols-%, based on the total quantity of diamines used, in order to obtain threads and fibres with tensile strengths and moduli of elasticity. 1

These diamines which contain hydantoin rings may, for example, be prepared as described in German Offenlegungsschrift 1,720,687 and German Offenlegungsschrift 1,720,733. Aromatic diamines which contain a hydantoin ring can be obtained by reacting N-substituted e-aminoacid nitriles or esters with aromatic isocyanates in a molar ratio of 1:1 in inert solvents and cyclising the resulting ureas to hydantoin derivatives, followed by reduction of the nitro groups.

When preparing these diamines, both the N- substituted a-aminocarboxylic acid nitriles or esters and the aromatic isocyanates may contain a nitro group right from the start or one or both nitro groups may be introduced by nitrating the hydantoin derivatives.

Suitable aromatic diamines in which two hydantoin rings separated by aromatic groups are situated between the two aromatic amino groups are, for example, those diamines which can be prepared in known manner by reacting a nitro-containing N-substituted on UK 3 5 0 l l o \C T-CH3 CH -(i H N@-i-i N@O@N N 0 NH 18) C u n o o 0 c CH on --c a N I: 2 l 1@NH 9) 2 2 '1 e i on on l 3 3 T I 'l l ll ll 0 o a-aminocarboxylic acid nitrile or ester of the following formula O N-Y-NH- C-GN or O N-Y-NH-C-CO0R O NYNCO with aromatic compounds which contain two a-aminocarboxylic acid nitrile groups or two a-aminocarboxydried and dissolved in the given polar solvents or in clilic acid ester groups in accordance with the following alkyl sulphoxides such as dimethyl sulphoxide. formula Spinning may in principle be carried out by the usual in which methods of dry or wet spinning. The polyamides are Y, Y, R, and R have the meanings defined above in preferably spun from solutions in dimethyl acetamide a molar ratio of 2:1, followed by ring closure and or N-methyl pyrrolidone which have polyamide solids reduction of the nitro groups. contents of between 12 and 25 The viscosities ofthe The third component consists of aromatic dicarbox- 15 spinning solutions are preferably between 500 and ylic acid dihalides of the general formula 1100 Poises (determined at C in a rotation viscosimeter) although solutions with viscosities of up to Hal OC Ar CO HaI v 2500 Poises can be spun without difficulty. The relative in which viscosity of the polyamides was between 1p 1.5 and Hal denotes Cl or Br and 20 17, 3, preferably between 1.8 and 2.5 (determined Ar has the meaning indicated above. on a 0.5 solution in concentrated sulphuric acid at The following are given as examples: C). lsophthalic acid dichloride, terephthalic acid dichlo- 1n the wet spinning process, the threads were coaguride, diphenyl-carboxylic acid-4,4'-dichloride, lated in an aqueous precipitation bath at 50-60C and naphthalene-dicarboxylic acid-1,5-dichloride, 25 drawn off from a IO-aperture die (aperture diameter naphthalene-dicarboxylic acid-2,6-dichloride, 0.1 mm) at a rate of 10-20 metres per minute. In the diphenylether-dicarboxylic acid 4,4'-dichloride, dry spinning process, the threads were extruded diphenylsulphone-dicarboxylic acid-4,4-dichloride, through the die (aperture diameter 0.1 mm) into a benzophenone-dicarboxylic acid-4,4-dichloride and spinning shaft charged with hot air at about 200C and the corresponding dibromides as well as alkyland drawn off at the rate of 100 metres per minute.

halogen-substitution products of the above mentioned The after-treatment is very important for producing acid dihalides. threads with good textile properties. Both wet spun and Terephthalic acid dichloride has been found to be dry spun threads are preferably first prestretched in particularly suitable for this invention. boiling water to a ratio of between 1:12 and 121.7 and Polycondensation of the 3 components described then washed in water at 60C and dried. The final above is carried out by known processes such as interstretching to a ratio of l:6l:l2 is carried out at a temface polycondensation but preferably by a process of perature of 420 to 500C.

solution polycondensation in polar organic solvents The tensile strengths of the stretched threads were such as N,N-dialkylcarboxylic acid diamines, preferabetween 7 and 20 g/dtex at l-3 elongation. The bly N,N-dimethylacetamide, or N-alkyl-substituted lac- 4O moduli ofelasticity were found to be between 5000 and tams, preferably N-methyl pyrrolidone, or in tetra- 11,000 kg.wt./mm

methyl urea or hexamethyl phosphoric acid triamide The following Examples are to further illustrate the etc. or in mixtures of such polar aprotic solvents in the invention without limiting it.

absence of additional acid acceptors but optionally in the presence of solubilising agents such as alkali metal EXAMPLE 1 or alkaline earth metal halides if they are necessary to 143.5 parts by weight of 4-amino-3'-(pkeep the copolyamides in solution. Condensation is aminophenoxy)-benzanilide of the formula carried out at a temperature of between 30 and 150C, preferably between -10 and 30C. The reaction times may be between 1 and 30 hours. The solids 5O content of the solutions is from 5 to 40 preferably 10 to 25 In order to obtain reaction products with the highest possible molecular weight, it is advisable to and 15.5 parts by weight of 1,3-bis-(p-aminophenyl)- use the sum of diamines and dicarboxylic acid dichlo- 5,5-dimethyl-hydantoin (1O mols-% based on the total ride components in equimolar quantities although the quantity of diamine) were dissolved in 780 parts by polycondensation may in principle also be carried out weight of anhydrous dimethyl acetamide. 101.5 parts with an excess or less than equivalent amount of dicarby weight of terephthalic acid dichloride were added in boxylic acid dichloride. The dicarboxylic acid dichlo- 3 portions over a period of about 2 hours at room temride may be added to the solution or suspension of diperature. When all the terephthalic acid dichloride had amines in solvent in several small portions spread over been added, the reaction mixture was diluted with 600 a considerable period of time but in some cases it is adparts by weight of dimethylacetamide and stirred at visable to add the total quantity of dicarboxylic acid diroom temperature for 6 hours. 58 parts by weight of chloride all at once and preferably with cooling. propylene oxide were then added dropwise to neutral- The polyamides may either be spun directly from the ise the hydrochloric acid formed. The neutral solution polycondensation solution, optionally after first neuhad a viscosity of 1050 Poises at 20C. The relative vistralising the hydrochloric acid, e.g. with ethylene oxide, cosity of the polymer, determined on a 0.5 solution propylene oxide or amines, or the polyamides may be in concentrated sulphuric acid of a sample of polyamprocessed into threads or fibres after they have been ide which had been precipitated with water and dried precipitated from the polycondensation solution with at C was 2.54. The polyamide solution was spun pre ipitating agents su h a at r, ls 0 s, into a water bath at 20C at a draw-off rate of 10 metres per minute. The threads were first prestretched in boiling water in the ratio of 121.3 and after drying they were finally stretched in the ratio of 1:7 on a roller at temperatures of between 440 and 460C.

The threads were found to have the following properties:

Tensile strength: 13-16 g/dtex Elongation on tearing: 2%

Modulus of elasticity: 8630 i 730 kg.wt./mm

The values for the elastic modulus are average values obtained from five measurements. Moisture absorption: 1.7%

EXAMPLE 2 239 parts by weight of 4-amino-3-(p-aminophenoxy)-benzanilide and 77.5 parts by weight of 1,3-bis(paminophenyl)-5,5-dimethylhydantoin (25 mo1s-% based on the total quantity of diamine) were dissolved in 1530 parts by weight of anhydrous N-methyl pyrrolidone, and 203 parts by weight of terephthalic acid dichloride were added portionwise at room temperature. A highly viscous solution was formed which was gradually diluted with a further 1450 parts by weight of N- methyl pyrrolidone. After a further 6 hours stirring at room temperature, 116 parts by weight of propylene oxide were added to neutralise the hydrochloric acid formed. The neutral solution had a viscosity of 940 Poises. The solids content was approximately 13 This solution was spun wet and the resulting threads were first prestretched in boiling water in the ratio of 1:13 and dried and then stretched in the ratio of 1:6 on a roller at temperatures of between 440 and 460C. n 2.09 (determined on a 0.5% solution in concentrated sulphuric acid).

The threads were found to have the following properties:

Tensile strength:

12-14 gldtex Elongation on tearing: 2-3 75 Modulus of elasticity: 8100 i 940 kg.wt./mm Moisture absorption: 2.1

EXAMPLE 3 100 parts by weight of 4-amino-3-methyl-3(2"- chro-4"-aminophenoxy)-benzanilide of the formula As described in detail in Example 1, the reaction mixture was diluted, neutralised and spun wet. The threads were stretched in the ratio of 128-10 at 450 to 460C.

Properties of the threads:

Tensile strength: 9-11 g/dtex Elongation on tearing: 1.5 Modulus of elasticity: 7800 i 820 kg.wt./mm Water absorption capacity: 1.8

EXAMPLE 4 282 parts by weight of 4-amino-3'-(2"-ch1oro-4"- amino-phenoxy)-benzanilide of the formula and 62 parts by weight of 1,3-bis-(p-aminophenyl)-5,5- dimethyl-hydantoin were polycondensed with 203 parts by weight of terephthalic acid dichloride as described in Example 1. The diluted solution neutralised with propylene oxide was spun wet. The resulting threads were stretched in the ratio 1:9-10 at about 450C.

The threads were found to have the following properties:

Tensile strength: Elongation on tearing: Modulus of elasticity: Moisture absorption:

1 1-14 g/dtex 9100 i 800 l g.wt./mm

We claim:

1. A high molecular weight aromatic copolyamide which consists essentially of from 50 to mol of structural units of the general formula R and R which may be the same or different, represent hydrogen, an alkoxy group, an alkyl group or a halogen atom,

R represents hydrogen, halogen, an alkyl, an alkoxy group, a nitrile group, a COOR, or -CONR R group and Ar represents a divalent aromatic group,

R denoting hydrogen or an alkyl group and R and R which may be the same or different, representing hydrogen, an alkyl group or aryl group and -50 mo] of structural units which contain hydantoin rings, which structural units are represented by the general formula in which Z represents a single bond or the group Hy Y and Y and Y may be the same or different and represent bivalent aromatic groups which comprise one or more condensed or several aromatic rings which are joined together by single bonds or by bridge members selected from the group consisting of O, S, SO2,

and the halo en-g alkyl-, No or CN-substitution products of such aromatic groups Hy represents a bivalent hydantoin ring of the formula ih which R represents hydrogen, alkyl, cycloalkyl, a phenyl group Ar represents a bivalent aromatic group wherein the copolyamides have a relative solution viscosity as determined on an 0.5% solution of the copolyamide in concentrated sulphuric acid at 25C of 5 from 1.5 to 3.0.

2. The copolyamide as claimed in claim 1 in which, in the general formula I, one or more of R, and R and R represent a C to C alkyl or an alkoxy group.

3. The copolyamide as claimed in claim 1 in which, in the general formula I of claim 1, one or more of R and R and R represent a C to C alkyl group.

4. The copolyamide as claimed in claim 1 in which, in the general formuala II of claim 1, Y, Y, or both rep resents a bivalent aromatic group which comprises several aromatic rings joined together by O, S,

-C-, S, -O-C r u 1' R 0 O or HN S0 groups.

5. The copolyamide as claimed in claim 1 in which, in the general formula II of claim 1, R represents a C, to C alkyl group.

6. The copolyamide as claimed in claim 1 in which, in the general formula I of claim 1, one or more of R and R and R represents chlorine.

7. The copolyamide as claimed in claim 1 in which, in the general formula I, R R or both represents a phenyl group, or a phenyl group substituted with chlorine or a C to C alkyl group.

8. The copolyamide as claimed in claim 1, which comprises from 70 to 90 mols-% of structural units of the general formula I and from 30 to 10 mols-% of structural units of the general formula II. 

2. The copolyamide as claimed in claim 1 in which, in the general formula I, one or more of R1 and R2 and R3 represent a C1 to C4 alkyl or an alkoxy group.
 3. The copolyamide as claimed in claim 1 in which, in the general formula I of claim 1, one or more of R4 and R5 and R6 represent a C1 to C4 alkyl group.
 4. The copolyamide as claimed in claim 1 in which, in the general formuala II of claim 1, Y, Y'', or both represents a bivalent aromatic group which comprises several aromatic rings joined together by -O-, -S-, -SO2-,
 5. The copolyamide as claimed in claim 1 in which, in the general formula II of claim 1, R7 represents a C1 to C4 alkyl group.
 6. The copolyamide as claimed in claim 1 in which, in the general formula I of claim 1, one or more of R1 and R2 and R3 represents chlorine.
 7. The copolyamide as claimed in claim 1 in which, in the general formula I, R5, R6 or both represents a phenyl group, or a phenyl group substituted with chlorine or a C1 to C4 alkyl group.
 8. The copolyamide as claimed in claim 1, which comprises from 70 to 90 mols-% of structural units of the general formula I and from 30 to 10 mols-% of structural units of the general formula II. 